This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Under the direction of G. Allan Johnson and Cristian Badea, this is a graduate student research project contributing to the geometric calibration for a dual tube/detector micro-CT system.